Model Output Discussion 01/06/2012

[phil nw.]

Welcome to the first day of the Meteorological Summer so this is a new thread for the new season.

Please keep to the subject matter and comment on what the models actually show.

This will help all visitors to enjoy this thread

[swilliam]

You can tell it is a BH coming up - a finger of green pointing unerringly at the UK

Longer term it looks a bit warmer but still decidedly wet.

Even into FI

Could be interesting meteorologically speaking though

[phil nw.]

The 00z outputs all show a rather unsettled and cool few days ahead with this coming weekend and bank holiday disappointingly cool with rain for many southern and central areas come Sunday into Monday.

The UKMO charts at T96 and T144hrs are typical of the overnight modelling.

The shallow upper trough still around the UK next week so no dramatic improvement is likely although maybe becoming a little warmer and brighter further south later.

[johnholmes]

There is still some uncertainty on just how far north the rain is going to get through Saturday night and Sunday but sadly its looking a cool couple of days and fairly wet for most areas south of about the Dee to the Humber; further north and it 'improves' in the sense that many places will be largely dry away from the southern fringe of Dee to Humber area, even some sunshine for some. Take a look at the outputs from GFS/Extra and the Met O NAE to confirm what I'm saying.

add into Monday for some as well re the rain and cool temperatures.

In the longer term then, again sadly, the link below shows how the ECMWF-GFS 500mb anomaly charts suggest the upper air might look in the 7-10 day time frame. The output from the NOAA equivalent last evening merely endorses this idea.

http://www.meteo.psu...0z/hgtcomp.html

Hardly a hot settled spell being indicated with a marked upper trough once again close by.

[Glacier Point]

I would concur with the idea of the 1st half of June being dominated by mean trough solution. The tropics are lit up at the moment and the centre of tropical forcing has shifted into the Indian Ocean and Martime Continent.

However, UKMO and GFS ensemble predictive tools both suggest the MJO and tropical forcing to shift back to Africa and eastern Pacific from mid month onwards, which would back our trough west drawing up some very warm weather. Not to sure on the timing of this, but last third of the month might well be interesting from a plume point of view.

[Summer Sun]

I would concur with the idea of the 1st half of June being dominated by mean trough solution. The tropics are lit up at the moment and the centre of tropical forcing has shifted into the Indian Ocean and Martime Continent.

However, UKMO and GFS ensemble predictive tools both suggest the MJO and tropical forcing to shift back to Africa and eastern Pacific from mid month onwards, which would back our trough west drawing up some very warm weather. Not to sure on the timing of this, but last third of the month might well be interesting from a plume point of view.

Thanks GP all looking good for a hot July hopefully

[Robbie Garrett]

I can see the Greenland height initially loosing any of it's support from the Azores. Good signs of the jetstream becoming distrupted as the Azores looks set to allow heights to be built over Europe. Low pressure seems to head north north eastwards as this happens, prompting some more settled weather in the 500+ hour mark. Look for hints of this in the later stages of fantasy island of the short range forecasting models, indications to me are the NAO/AO are heading for a more neutral state, for how long is open to debate.

Personally you can already see evidence of an eventual breakdown of northern heights as there isn't any sufficient connection of warm air being promoted towards Greenland, expect a rather unsettled period upcoming though.

Models ensembles highly indicative of a pressure drop to our north west, some strong agreement to go with this too, literally all model ensembles till 8th June 2012.

No agreement yet on high pressure looking to rise across Europe, UK. But some good suggestions of something.

Percipitation values, quite modest considering the monsoon season normally provides.

Atlantic train anyone??

Bare with the weather, it may provide...

[NorthNorfolkWeather]

To emphasise the fact that the models are struggling, just look at the differences between GFS and ECM at 144,

then at 240

quite significant variations on what the country can expect with the ECM being colder and wetter to start with but improving greatly compared to the GFS

[shedhead]

It might well be deep FI, but with heights like this over Greenland very little if anything is going to change across NW Europe.

[shedhead]

I would concur with the idea of the 1st half of June being dominated by mean trough solution. The tropics are lit up at the moment and the centre of tropical forcing has shifted into the Indian Ocean and Martime Continent.

However, UKMO and GFS ensemble predictive tools both suggest the MJO and tropical forcing to shift back to Africa and eastern Pacific from mid month onwards, which would back our trough west drawing up some very warm weather. Not to sure on the timing of this, but last third of the month might well be interesting from a plume point of view.

So a potential repeat performance of May then and to be fair, looking at the latest outputs, the last 1/3rd appears the only viable option on the table for now.

[tinybill]

http://www.meteociel.fr/modeles/gfse_cartes.php?mode=2&ech=6

i know i keep going on about it but at the moment if f1 play out june looks its going to be a wash out, and i know people on here what the sun but at the moment its not looking good at the moment!!!

[NorthNorfolkWeather]

I dislike this term. There are going to be differences; some big, some small. There's nothing abnormal about seeing large divergence in NWP outputs. It's what we should expect from weather models calculating/predicting the atmosphere's "next move".

If you think about it, though, the models are always struggling, because they *never* model a period in the future with 100% accuracy.

Nothing wrong in what I say, or what you say, just different sides of the same coin.

I think my main emphasis was that even at T144 the differences were, to me at least, significant..

I agree that we *never* have models that accurately predict what will happen, but generally the divergence happens post T144

[shedhead]

I dislike this term. There are going to be differences; some big, some small. There's nothing abnormal about seeing large divergence in NWP outputs. It's what we should expect from weather models calculating/predicting the atmosphere's "next move".

If you think about it, though, the models are always struggling, because they *never* model a period in the future with 100% accuracy.

Agreed, the models are not struggling, far from it. OK there are some medium and even short term differences, but nothing new there to be honest. Overall they are in very good agreement on a cool, unsettled pattern well into June, which unfortunately has a very familiar look about it from recent summers.

[Robbie Garrett]

It might well be deep FI, but with heights like this over Greenland very little if anything is going to change across NW Europe.

I think the likely scenario is heights build across Europe, low pressure stalls out in the Atlantic cutting off the supply towards Greenland from the Azores, and the Azores then ridges towards Europe prompting further warmer conditions, otherwise the NAO will again likely head negative. That's my perspective of any upcoming pattern change, and the models will likely not show it till 11pm the night before (something silly like that).

[shedhead]

Agreed, troughing will eventually ease west, allowing warmer air to get advected north across the UK, but atm the emphasis remains on the word eventually... this evolution is some considerable way off imo.

[samadamsuk]

HI All.

Quick post from me - IMO the first signal that we were coming out of the rut before the last warm spell was warm air advection over Sweden/Finland heading out due west into the atlantic, and forcing the polar outflow (that's usualy stuck over us!) to head east across the top of the continent - there are tentative signs of this happening again so will be interesting to see where we go from here

Cheers, Sam

[Summer Sun]

Seems that the met office agree with GP's update this morning

Towards the end of the month, indications are that these drier and brighter periods may become more prolonged, with rainfall amounts falling closer to the seasonal average. After a rather cool start with temperatures generally slightly below average, it should gradually become a little warmer and sunnier in places.

http://www.metoffice.gov.uk/weather/uk/uk_forecast_weather.html

[Robbie Garrett]

Looking pretty good on the CFS 1 month model IMHO aswell, could be the first of many Plumes looking at the models, good chance of hottest temperatures since 2003 being recorded in the South East, with 20*C 850HPA being advected this direction on many occasions.

[Summer Sun]

Unsettled from GFS again tonight, hopefully it will begin to show some high pressure soon for later in the month as predicted

http://www.jp2webdes...o.uk/ds/gfs.htm

[Snow Shoes]

I think the likely scenario is heights build across Europe, low pressure stalls out in the Atlantic cutting off the supply towards Greenland from the Azores, and the Azores then ridges towards Europe prompting further warmer conditions, otherwise the NAO will again likely head negative. That's my perspective of any upcoming pattern change, and the models will likely not show it till 11pm the night before (something silly like that).

Yes but thats

HI All.

Quick post from me - IMO the first signal that we were coming out of the rut before the last warm spell was warm air advection over Sweden/Finland heading out due west into the atlantic, and forcing the polar outflow (that's usualy stuck over us!) to head east across the top of the continent - there are tentative signs of this happening again so will be interesting to see where we go from here

Cheers, Sam

Yes but since those tentative signs don't appear until well into f1 (lala-land) territory, i wouldn't attach much significance to it until you see the same signals repeated within more reliable T144 time frame. My gut feeling at the moment is that we're on course for a rinse repeat of Summer 2007/2009

[Summer Sun]

Yes but thats

Yes but since those tentative signs don't appear until well into f1 (lala-land) territory, i wouldn't attach much significance to it until you see the same signals repeated within more reliable T144 time frame. My gut feeling at the moment is that we're on course for a rinse repeat of Summer 2007/2009

Hopefully that won't be the case with both Netweather and The weather outlook going for somthing much better

[Backtrack]

I would concur with the idea of the 1st half of June being dominated by mean trough solution. The tropics are lit up at the moment and the centre of tropical forcing has shifted into the Indian Ocean and Martime Continent.

However, UKMO and GFS ensemble predictive tools both suggest the MJO and tropical forcing to shift back to Africa and eastern Pacific from mid month onwards, which would back our trough west drawing up some very warm weather. Not to sure on the timing of this, but last third of the month might well be interesting from a plume point of view.

I'm surprised you have any fingers left after writing that summer forecast. Not only was that the longest forecast I have ever seen, but also the best. Well done.

[Steve C]

Yes but thats

Yes but since those tentative signs don't appear until well into f1 (lala-land) territory, i wouldn't attach much significance to it until you see the same signals repeated within more reliable T144 time frame. My gut feeling at the moment is that we're on course for a rinse repeat of Summer 2007/2009

I think I'd rather have an interpretation of model signals, than your 'gut feel' though, even if the models are well into FI

[Summer Sun]

Unsettled from UKMO tonight

http://www.null/ds/ukmo.htm

Wonder if ECM will offer anything different

[Luke McDonnell]

Yes but thats

Yes but since those tentative signs don't appear until well into f1 (lala-land) territory, i wouldn't attach much significance to it until you see the same signals repeated within more reliable T144 time frame. My gut feeling at the moment is that we're on course for a rinse repeat of Summer 2007/2009

Hi,

Just saying that GP does make the point in his Summer forecast that looking at all the various factors (ENSO, QBO, SST's etc) he does not see a 2007 style summer as being likley and the these variables were a lot different back in 2007 - quote: "what variability there is coming from one guiding force and the theme will be of steady evolution and there is no indication whatsoever of a 2007 type summer which was characterised by a sharp increase in easterly winds over the Arctic."

What amazes me is how some folks go straight for the worst case scenario when poor synopics are being shown by the models. 2007 being mentioned proves the point. Remember that 2007 was pretty exceptional as far as rainfall is concerned - 2007 was probably as exceptional as summers like 1976 and 2006 but for different reasons and statistically the likelyhood of a repeat this summer is low. Also remember that 2007 as a year was quite different to 2012 - in 2007 thier was a warm and dry April but most of this years was cool and wet. As for 2009 I think a 2009 (or say a 2005) type summer would be more likely than 2007 considering those years were closer to an average British summer without the incessent rainfall that 2007 brought.

Luke